2-42769785-C-T

Position:

• chr2-42769785-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_012205.3(HAAO):​c.558G>A​(p.Trp186*) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HAAO NM_012205.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 4.03

Genes affected

HAAO (HGNC:4796): (3-hydroxyanthranilate 3,4-dioxygenase) 3-Hydroxyanthranilate 3,4-dioxygenase is a monomeric cytosolic protein belonging to the family of intramolecular dioxygenases containing nonheme ferrous iron. It is widely distributed in peripheral organs, such as liver and kidney, and is also present in low amounts in the central nervous system. HAAO catalyzes the synthesis of quinolinic acid (QUIN) from 3-hydroxyanthranilic acid. QUIN is an excitotoxin whose toxicity is mediated by its ability to activate glutamate N-methyl-D-aspartate receptors. Increased cerebral levels of QUIN may participate in the pathogenesis of neurologic and inflammatory disorders. HAAO has been suggested to play a role in disorders associated with altered tissue levels of QUIN. [provided by RefSeq, Jul 2008]

HAAO (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-42769785-C-T is Pathogenic according to our data. Variant chr2-42769785-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 403728.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-42769785-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HAAO	NM_012205.3	c.558G>A	p.Trp186*	stop_gained	7/10	ENST00000294973.11	NP_036337.2
HAAO	XM_011532729.4	c.468G>A	p.Trp156*	stop_gained	6/9		XP_011531031.1
HAAO	XM_011532730.4	c.456G>A	p.Trp152*	stop_gained	8/11		XP_011531032.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HAAO	ENST00000294973.11	c.558G>A	p.Trp186*	stop_gained	7/10	1	NM_012205.3	ENSP00000294973.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Vertebral, cardiac, renal, and limb defects syndrome 1 Pathogenic:2

Pathogenic, criteria provided, single submitter	curation	SIB Swiss Institute of Bioinformatics	Apr 16, 2018	This variant is interpreted as a Pathogenic, for Vertebral, cardiac, renal, and limb defects syndrome 1, Autosomal Recessive inheritance. The following ACMG Tag(s) were applied: PM2 => Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium. PVS1-Strong => PVS1 downgraded in strength to Strong. PS3 => Well-established functional studies show a deleterious effect (PMID:28792876). -
Pathogenic, no assertion criteria provided	literature only	OMIM	Sep 21, 2017	- -

Congenital NAD deficiency disorder Pathogenic:1

Pathogenic, criteria provided, single submitter

research

Embryology Laboratory, Victor Chang Cardiac Research Institute

Dec 23, 2016

This variant was discovered in a consanguineous family of Middle East origin. The patient presented multiple congenital malformations affecting vertebrae, heart and kidney among others. This variant is a protein truncating variant and novel (ExAC MAF 0). The patient is homozygous, while her unaffected parents and three unaffected siblings are heterozygous for this variant. The patient showed increased plasma concentration of 3HAA and reduced plasma concentration of NAD, consistent with loss of function of the HAAO enzyme activity. Enzyme assay confirmed that the protein product of this gene variant has lost enzyme activity. Mouse embryos homozygous null for Haao presented similar phenotype as observed in the patient, and also showed reduced concentration of NAD in the embryonic tissue. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Pathogenic	0.77
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Benign	0.66	D
Vest4		0.36
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1135401743; hg19: chr2-42996925;